Bioresin composition for use in forming a rigid polyurethane foam article

ABSTRACT

A bioresin composition is used to form a rigid polyurethane article that includes a first and a second biopolyol and is substantially free of aprotic solvents that chemically decompose in the presence of water. The first biopolyol includes a natural oil component. The second biopolyol includes the reaction product of a natural carbohydrate and an alkylene oxide. The rigid polyurethane foam article includes the reaction product of the bioresin composition and an isocyanate which are reacted in the presence of a chemical blowing agent.

RELATED APPLICATIONS

This application claims priority to and all advantages of U.S.Provisional Patent Application No. 61/186,288, which was filed on Jun.11, 2009.

FIELD OF THE INVENTION

The present invention generally relates to a rigid polyurethane foamarticle which is the reaction product of a bioresin composition and anisocyanate. More specifically, the bioresin composition includes firstand second biopolyols and is substantially free of aprotic solvents thatchemically decompose in the presence of water.

DESCRIPTION OF THE RELATED ART

Polyurethane foam articles are used extensively in a wide array ofcommercial and industrial applications. The popularity of polyurethanefoam articles is due in part to the fact that the physical properties ofa polyurethane foam article may be selectively altered based on aformulation of reactants which form the polyurethane foam article. Theformulation may be developed to provide a polyurethane foam article thatis soft, flexible and open-celled which, can be used in applicationssuch as seat cushions. On the other hand, the formulation may bedeveloped to provide a polyurethane foam article that is rigid,structural, thermally resistant and closed-celled which, can be used asa thermal insulation panel.

The most common method of forming polyurethane foam articles is themixing and, subsequent reaction, of a polyol (e.g. a resin composition)with an isocyanate in the presence of a blowing agent. Generally, whenthe resin composition is mixed with the isocyanate to form a reactionmixture in the presence of the blowing agent, a urethane polymerizationreaction occurs. As the urethane polymerization reaction occurs, thereaction mixture cross-links to form the polyurethane and gas issimultaneously formed and released. Through the process of nucleation,the gas foams the reaction mixture thereby forming voids or cells in thepolyurethane foam article.

The resin composition typically comprises one or more polyols, a cellopening agent, a cross linking agent, a catalyst, an adhesion promotingagent and various additives. The blowing agent creates the cells in thepolyurethane foam article as described above. The cell opening agenthelps open the cells so that the cells form an interconnected networkand improves the stability of the polyurethane foam article. Thecross-linking agent promotes cross-linking of the reaction mixture whichresults in the polyurethane foam article. The catalyst controls reactionkinetics to improve the timing of the polymerization reaction bybalancing a gel reaction and the blowing agent to create thepolyurethane foam article, which is stable. The adhesion promoting agent(e.g. an aprotic solvent) facilitates wet out of the reaction mixtureand promotes adhesion of the polyurethane foam article to substratesupon which the polyurethane foam article is disposed. For example, thesubstrate may be a thermoplastic shell or thermoplastic liner of apicnic cooler. The density and rigidity of the polyurethane foam articlemay be controlled by varying the chemistry of the isocyanate, the resincomposition and/or the blowing agent, and amounts thereof.

A thermal insulating device such as the picnic cooler described abovetypically comprises a thermoplastic shell and a thermal core. Structuralintegrity and physical properties of a rigid polyurethane foam articlemake it an excellent thermal core for such a picnic cooler. When therigid polyurethane foam article is used as the thermal core in thismanner, the rigid polyurethane foam article not only provides thermalresistance, but the rigid polyurethane foam article also holds thepicnic cooler together with cohesive and adhesive properties. The rigidpolyurethane foam article typically fills the thermoplastic shell of thepicnic cooler and wets out the inner surfaces of the thermoplastic shelluniformly, such that exterior surfaces of the picnic cooler are free ofvisual defects and the picnic cooler does not fall apart during use.When the resin composition is free of the aprotic solvent, the reactionmixture does not adequately wet out and sufficiently adhere to thethermoplastic shell and thermoplastic liner. Further, many aproticsolvents chemically decompose in the presence of water, generatingcarbon dioxide. Decomposition of the aprotic solvent in the resincomposition and concurrent release of carbon dioxide typicallypressurizes resin storage containers, and in extreme cases causes theresin storage container to fail.

Furthermore, conventional polyurethane foam articles are made frompetroleum based polyols. As a non-renewable feedstock, petroleum hasboth environmental and financial drawbacks. Accordingly, there areenvironmental, economic, and commercial advantages associated with theuse of polyols based on renewable feedstock to make bio-basedpolyurethane foam articles. Biopolyols are considered a good alternativeto petroleum-based polyols for the production of bio-based polyurethanefoam articles. Typically, biopolyols include one or more modifiednatural oils, natural carbohydrates or other renewable feedstocks.

In view the foregoing, it would be advantageous to develop an improvedrigid polyurethane foam article, the rigid polyurethane foam articleformed from a bioresin composition. The rigid polyurethane foam articlehaving exception cell structure and rigidity, robust adhesion tothermoplastic substrates and excellent thermal resistance.

SUMMARY OF THE INVENTION AND ADVANTAGES

The instant invention provides a bioresin composition. The bioresincomposition is substantially free of aprotic solvents that chemicallydecompose in the presence of water. The bioresin composition includes(i) a first biopolyol comprising a natural oil component. The bioresincomposition further includes (ii) a second biopolyol comprising thereaction product of a natural carbohydrate and an alkylene oxide. Thesecond biopolyol is present in excess relative to the first biopolyol ina weight ratio of from greater than 1:1 to about 3:1. The bioresincomposition also includes an aprotic solvent that does not chemicallydecompose in the presence of water. The bioresin composition is reactedwith an isocyanate in the presence of a chemical blowing agent to form arigid polyurethane foam article.

The bioresin composition is particularly useful for the formation of therigid polyurethane foam article. The rigid polyurethane foam article isan excellent thermal core for a thermal insulating device. The rigidpolyurethane foam article has physical properties that are attributable,at least in part, to the bioresin composition and selection of the firstbiopolyol and the second biopolyol, as well as the ratio therebetween.In addition, use of the aprotic solvent that does not decompose in thepresence of water reduces a chance of the bioresin compositiongenerating gas (e.g. carbon dioxide) and pressurizing resin containersused to store and transport the bioresin composition. The bioresincomposition of the present invention reduces a chance that the resincontainers will become pressurized and fail from the gas formingchemical reaction of an aprotic solvent and water. The bioresincomposition also reduces a need to use specially vented and/or explosionproof resin containers.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a rigid polyurethane foam article that isherein after referred to as an “article”. The article may be formedwithin a cavity or between two substrates, molded, formed into boards,or foamed-in-place to form an article that molds and adheres tocontacting surfaces. In one embodiment, the article is further definedas a thermal core disposed between an outer and an inner wall of athermal insulating device such as a picnic cooler. In other embodiments,the article is used in a variety of applications such as inrefrigeration appliances or building and construction products. Ofcourse, the article of the present invention is not limited to theseembodiments.

The article adheres to various substrates, while exhibiting excellentthermal transmission properties. As is well know in the art, thermaltransmission properties include thermal resistance and thermalconductivity. Thermal resistance is related to a K-factor; the greaterthe thermal resistance the lower the K-factor. Typically, the K-factoris measured in accordance to ASTM C 518.

The article includes a reaction product of a bioresin composition and anisocyanate which react in the presence of a blowing agent. Theisocyanate and the blowing agent are described in greater detail below.The bioresin composition, herein after referred to as a “composition”,includes a first and a second biopolyol and is substantially free ofaprotic solvents that chemically decompose in the presence of water. Thephysical properties of the article may be controlled by varying thecomposition of the bioresin composition.

The terminology “substantially free”, as used herein in reference to theaprotic solvent that chemically decomposes in the presence of water,refers to a sufficiently low amount of the aprotic solvent, such thatgeneration of CO₂ gas is minimized. Typically, the amount of the aproticsolvent that chemically decomposes in the presence of water that ispresent in the composition is less than 5, more typically less than 0.5,still more typically less than 0.1, and most typically zero, percent byweight based on the total weight of the composition.

As first described above, the composition includes the first biopolyol.The first biopolyol typically has a nominal functionality of greaterthan 1.5 and more typically of greater than 2.5. The first biopolyolalso typically has a hydroxyl number of from about 200 to about 550,more typically of from about 400 to about 550, and most typically offrom about 425 to about 525, mg KOH/g as calculated using ASTM D4274.The first biopolyol also typically has a viscosity of from about 500 toabout 1500 and most typically of from about 750 to about 1250, cps at77° F., when tested with a Brookfield viscometer using a No. 21 spindleand at various speeds depending on the polyol. The speed of the spindleis determined by the percent torque specific to the polyol and is setwhen the measurement is in the center of the scale or higher.

The first biopolyol includes a natural oil component. The natural oilcomponent includes at least one natural oil, the reaction product of atleast one natural oils and a compound reactive therewith, andcombinations thereof. A natural oil may be further defined as atriglyceride. Alternatively, natural oils may include a mixture ofdiffering triglycerides. One particularly suitable natural oil is castoroil. As is well known in the art, castor oil is produced directly from aplant source and includes hydroxyl groups. Other natural oils, which donot have hydroxyl groups, and which have carbon-carbon double bonds,typically require oxidation of the carbon-carbon double bonds to formhydroxyl groups. Some suitable natural oils include but are not limitedto canola oil, castor oil, peanut oil, soy bean oil and combinationsthereof.

A particularly suitable first biopolyol is PEL-SOY™ 744 sold under thetrademark PEL-SOY™ and commercially available from Pelron Corporation.PEL-SOY™ 744 is a soy bean oil based biopolyol having a nominalfunctionality of 2.5, a hydroxyl number of 474 mg KOH/g, and a viscosityof 1031 cps at 77° F. Specific examples of other first biopolyols thatare suitable for the purposes of the present invention include, but arenot limited to: SOYOL™ R22-052-G and SOYOL™ R3-170-G, both sold underthe trademark SOYOL™ and commercially available from Urethane SoySystems Company; POYLCIN® GR-35, POYLCIN® GR-340, POYLCIN® D-265, andPOYLCIN® T-400, all sold under the trademark POYLCIN® and commerciallyavailable from Vertellus; VIKOL™ 1 sold under the trademark VIKOL™ andcommercially available from Arkema Corporation; biopolyols sold underthe trademark RENUVA™ and commercially available from Dow ChemicalCorporation; biopolyols sold under the trademark BiOH™ and commerciallyavailable from Cargill Corporation; and AGROL® 2.0, AGROL® 3.0, AGROL®4.0, AGROL® 5.0, AGROL® 6.0, and AGROL® 7.0, all sold under thetrademark AGROL® and commercially available from BioBased Technologies.Of course, the first biopolyol may include any combination of two ormore of the aforementioned first biopolyols. The first biopolyol istypically present in the composition in an amount of from about 10 toabout 100, more typically of from about 15 to about 70, and mosttypically of from about 20 to about 70, parts by weight based on 100parts by weight of the composition.

In addition to the first biopolyol, the composition also includes thesecond biopolyol which is different from the first biopolyol. The secondbiopolyol typically has a nominal functionality of greater than 2.0, andmore typically of greater than 4.0. The second biopolyol also typicallyhas a hydroxyl number of from about 250 to about 550, more typically offrom about 300 to about 450, and most typically of from about 360 toabout 375, mg KOH/g as calculated by ASTM D4274. The second biopolyoltypically has a viscosity of from about 2000 to about 5000, mosttypically of from about 3000 to from about 4000 and most typically offrom about 3250 to about 3750, cps at 77° F., when tested with aBrookfield viscometer using a No. 21 spindle and at various speedsdepending on the polyol. The speed of the spindle is determined by thepercent torque specific to the polyol and is set when the measurement isin the center of the scale or higher.

The second biopolyol includes the reaction product of a naturalcarbohydrate and an alkylene oxide. Natural carbohydrates include sugarssuch as monosaccharides or disaccharides, and sugar alcohols. As is wellknow in the art, sugar alcohols are hydrogenated sugars whose carbonylgroup has been reduced to a primary or secondary hydroxyl group. Oneexample of a natural carbohydrate is sacharose from sugar beets. Othersuitable examples include, but are not limited to fructose, galactose,glucose, lactose, maltose, trehalose, and cellobiose. Preferably, thealkylene oxide that reacts with the natural carbohydrate to form thepolyol is selected from the group of ethylene oxide, propylene oxide,butylene oxide, amylene oxide, tetrahydrofuran, alkyleneoxide-tetrahydrofuran mixtures, epihalohydrins, aralkylene oxides, andcombinations thereof. More preferably, the alkylene oxide is selectedfrom the group of ethylene oxide, propylene oxide, and combinationsthereof. However, it is also contemplated that any suitable alkyleneoxide that is known in the art may be used in the present invention.

A particularly suitable second biopolyol is PLURACOL® SG-360 sold underthe trademark PLURACOL® and commercially available from BASFCorporation. PLURACOL® SG-360 is a saccharose based biopolyol having, anominal functionality of 4.0, a hydroxyl number of 368 mg KOH/g, and aviscosity of 3500 cps at 77° F. Other sucrose based second biopolyolswith functionalities similar to this one are particularly suitable aswell. Of course, the second biopolyol may include any combination of twoor more second biopolyols.

The second biopolyol is typically present in the composition in anamount of from about 10 to from about 100, more typically in an amountof from about 15 to from about 70, and most typically in an amount offrom about 40 to from about 60, parts by weight based on 100 parts byweight of the composition. Accordingly, the second biopolyol istypically present in the composition in weight excess relative to thefirst biopolyol. A weight ratio of the first biopolyol to the secondbiopolyol in the composition is typically of from about 2.0:1.0 to about1.0:4.0, more typically of from about 1.0:1.0 to about 1.0:3.0, and mosttypically of from about 1.0:1.0 to about 1.0:2.5. The selection and theratio of the first and second biopolyol are important to the formationof the article. When forming the article, this ratio contributes tooptimal processing conditions, such as viscosity and reaction speed.Furthermore, the ratio contributes a crosslink density needed to form asuitable article, i.e., a rigid polyurethane foam article havingexcellent cell strength and foam structure.

In addition to the first and second biopolyols, the composition may alsoinclude a supplemental polyol that is different than the first andsecond biopolyols. The supplemental polyol typically includes thereaction product of toluenediamine and the alkylene oxide, as describedabove. The supplemental polyol typically has a nominal functionality ofgreater than 2.0, and more typically of greater than 4.0. Thesupplemental polyol also typically has a hydroxyl number of from about200 to about 700, more typically of from about 300 to about 450, andmost typically of from about 438 to about 465, mg KOH/g as calculated byASTM D4274. The supplemental polyol also typically has a viscosity offrom about 3000 to about 800, most typically of from about 4000 to fromabout 7000 and most typically of from about 5000 to about 6000, cps at77° F., when tested with a Brookfield viscometer using a No. 21 spindleand at various speeds depending on the polyol. The speed of the spindleis determined by the percent torque specific to the polyol and is setwhen the measurement is in the center of the scale or higher.

A particularly suitable supplemental polyol is PLURACOL® P-735 soldunder the trademark PLURACOL® and commercially available from BASFCorporation. PLURACOL® P-735 has a nominal functionality of at least 4,a hydroxyl number of from about 438 to about 465 mg KOH/g, and aviscosity of 5,500 cps at 77° F. Additional non-limiting examples ofsupplemental polyols that are suitable for use in the present inventioninclude PLURACOL® P-1158 and PLURACOL® P-2097 both also sold under thetrademark PLURACOL® and commercially available from BASF Corporation. Itis to be appreciated that the supplemental polyol may include anycombination of two or more of the aforementioned supplemental polyols.The supplemental polyol is typically present in the composition in anamount less than or equal to about 50, more typically in an amount lessthan or equal to about 35, and most typically in an amount less than orequal to about 15, parts by weight based on 100 parts by weight of thecomposition.

The composition also includes an aprotic solvent that does notchemically decompose in the presence of water. The aprotic solvent isstable in the presence of water and will not typically decompose intoone or more chemical compounds (e.g. gasses) in the presence of water.The aprotic solvent that does not chemically decompose in the presenceof water typically functions as an adhesion promoter in the composition.This aprotic solvent of the present invention provides ionic properties,without donating an acidic hydrogen molecule, to a reaction mixturecomprising the composition and the isocyanate. The ionic properties ofthe aprotic solvent promotes uniform wetting out of surfaces, thusallowing for improved adhesion of the article to the surfaces.

Suitable examples of aprotic solvents that do not decompose in thepresence of water include but are not limited to diethyl carbonate,chloroform, N,N-dimethylacetamide, dimethyl sulfoxide,N,N-dimethylformamide, dimethylpropylene urea, dimethyl carbonate,dioxane, ethyl methyl carbonate, hexamethylphosphorotriamide,N-methylpyrrolidinone, tetrahydrofuran, and triethyl phosphate. It is tobe appreciated that the aprotic solvent that does not chemicallydecompose in the presence of water may include any combination of two ormore of the aforementioned aprotic solvents that do not chemicallydecompose in the presence of water. A particularly suitable aproticsolvent that does not chemically decompose in the presence of water istriethyl phosphate commercially available from Eastman Corporation.Generally, triethyl phosphate is readily available and is advantageousfrom a health and safety standpoint. The aprotic is typically present inthe composition in an amount of from about greater than 0 to about 15,more typically of from greater than 0 to about 10, and most typically offrom about 3 to from about 7.5, parts by weight based on 100 parts byweight of the composition.

The composition of the present invention also typically includes a fattyacid as a cell opening agent. The cell opening agent helps open thecells of the article so that the cells form an interconnected networkwithin the article and to improve foam stability. In one embodiment,wherein the article is molded to fill the core of the thermal insulatingdevice, open celled content is desired.

The fatty acid of this invention is typically an organic carboxylic acid(mono and/or dibasic) having from 7 to 100 carbon atoms, more typicallyfrom 10 to 25 carbon atoms, and most typically from 12 to 18, carbonatoms. The fatty acid can be saturated or unsaturated, aliphatic orcycloaliphatic, unsubstituted or substituted with other functionalgroups such as hydroxyl groups. Suitable fatty acids include, but arenot limited to, lauric acid, myristoleic acid, palmotoeic acid, palmiticacid, linoleic acid, oleic acid, acetyl acid, and stearic acid. Mixturesof two or more of the above described cell fatty acids can be used. Aparticularly suitable fatty acid is oleic acid. The fatty acid istypically present in the composition in an amount of from 0.1 to fromabout 20.0 parts by weight, typically between 0.5 and 5.0 by weight andmost typically between 0.5 and 2.0 parts based on 100 parts by weight ofthe composition.

Moreover, the composition may also include a surfactant or more than onesurfactant. Suitable surfactants include conventional surfactants knownin the art, such as anionic, cationic, non-ionic surfactants, andmixtures thereof. Suitable nonionic surfactants typically include thoseprepared by sequential addition of propylene oxide and then ethyleneoxide to propylene glycol, solid or liquid organosilicones, polyethyleneglycol ethers of long chain alcohols, tertiary amines or alkylolaminesalts of long chain alkyl acid sulfate esters, alkyl sulfonic ester andalkyl arylsulfonic acids. Liquid organosilicones, specifically thosethat are not hydrolyzable, are also useful. A specific, non-limitingexample of a suitable surfactant is DABCO® DC 5604, a siliconesurfactant, sold under the trademark DABCO® and commercially availablefrom Air Products and Chemicals, Inc. Another specific, non-limitingexample of the suitable surfactant is TEGOSTAB® B 8433, a siliconesurfactant sold under the trademark TEGOSTAB® and commercially availablefrom Evonik. It is to be appreciated that the surfactant may include anycombination of two or more of the aforementioned surfactants. Thesurfactant may be included in the composition in various amounts. Incertain embodiments, the surfactant is present in an amount of fromabout 0.5 to about 10, more typically from about 0.5 to about 5, andmost typically from about 0.5 to about 3, parts by weight based on 100parts by weight of the composition.

The composition may also include a catalyst which catalyzes the reactionof the composition and the isocyanate in the reaction mixture, firstdescribed above. The catalyst promotes cross-linking of the reactionmixture to form article. The catalyst is thought to influence reactionkinetics to help tailor the physical properties of the article. In oneembodiment, the catalyst includes at least one tertiary amine catalyst.Examples of tertiary amine catalysts that are particularly useful forpurposes of the present invention include, but are not limited todimethylaminoethanol, dimethylaminoethoxyethanol, triethylamine,N,N,N′,N′-tetramethylethylenediamine, N,N-dimethylaminopropylamine,N,N,N′,N′,N″-pentamethyldipropylenetriamine, tris(dimethylaminopropyl)amine, N,N-dimethylpiperazine,tetramethylimino-bis(propylamine), dimethylbenzylamine, trimethylamine,triethanolamine, N,N-diethyl ethanolamine, N-methylpyrrolidone,N-methylmorpholine, N-ethylmorpholine, bis(2-dimethylamino-ethyl)ether,N,N-dimethylcyclohexylamine (DMCHA), pentamethyldiethylenetriamine,1,2-dimethylimidazole, 3-(dimethylamino) propylimidazole, andcombinations thereof. Specific, non-limiting examples of suitabletertiary amine catalysts are DABCO® DMCHA, DABCO® 33LV, DABCO® BL-17,and DABCO® BL-19 all sold under the trademark DABCO® and commerciallyavailable from Air Products and Chemicals, Inc. Another specific,non-limiting example of the suitable tertiary amine catalyst is POLYCAT®12 sold under the trademark POLYCAT® also commercially available fromAir Products and Chemicals, Inc. The catalyst is typically present in anamount of from about 0.01 to about 3.5, more typically from about 0.05to about 2.5, and most typically from about 0.05 to about 1.5, parts byweight, based on 100 parts by weight of the composition. It is to beappreciated that the catalyst may include any combination of two or moreof the aforementioned catalysts.

Still further, the composition may include one or more additives. Theone or more additives may include, but are not limited to, additionalcatalysts used to enhance the formation of the article, such as tincatalysts (e.g. tin octoate and dibutyltindilaurate), imidazoles (e.g.dimethylimidazole), maleate esters, acetate esters, fire retardants,smoke suppressants, UV-stabilizers, colorants, microbial inhibitors andfillers and any combination thereof.

As described above, the composition is reactive with the isocyanate inthe presence of the blowing agent. The isocyanate is typically anorganic polyisocyanate having two or more functional groups, e.g. two ormore NCO functional groups. Suitable organic polyisocyanates, forpurposes of the present invention include, but are not limited to,conventional aliphatic, cycloaliphatic, araliphatic and aromaticisocyanates. In various embodiments, the isocyanate is selected from thegroup of diphenylmethane diisocyanates (MDIs), polymeric diphenylmethanediisocyanates (pMDIs), toluene diisocyanates (TDIs), hexamethylenediisocyanates (HDIs), isophorone diisocyanates (IPDIs), and combinationsthereof.

In another embodiment, the isocyanate is further defined as anisocyanate-terminated prepolymer. The isocyanate-terminated prepolymeris typically a reaction product of an isocyanate and a polyol and/or apolyamine. The isocyanate may be any type of isocyanate known to thoseskilled in the polyurethane art, such as one of the organicpolyisocyanates described above. The polyol used to form the prepolymeris typically selected from the group of ethylene glycol, diethyleneglycol, propylene glycol, dipropylene glycol, butane diol, glycerol,trimethylolpropane, triethanolamine, pentaerythritol, sorbitol,biopolyols, such as soybean oil, castor-oil, soy-protein, rapeseed oil,and combinations thereof. The polyamine used to form the prepolymer istypically selected from the group of ethylene diamine, toluene diamine,diaminodiphenylmethane and polymethylene polyphenylene polyamines,aminoalcohols, and combinations thereof. Examples of suitableaminoalcohols include ethanolamine, diethanolamine, triethanolamine, andcombinations thereof.

Specific examples of suitable isocyanates include LUPRANATE™ M,LUPRANATE™ ME, LUPRANATE™ MI, and LUPRANATE™ M205, all sold under thetrademark LUPRANATE™ and commercially available from BASF Corporation.Typically, the isocyanate is present in an amount of from about 25 toabout 60, more typically from about 30 to about 50, and most typicallyfrom about 35 to about 45, parts by weight, based on 100 parts by weightof the article. It is to be appreciated that the isocyanate may includeany combination or two of more of the aforementioned isocyanates andisocyanate-terminated prepolymers.

Also described above, the bioresin composition is reacted with theisocyanate in the presence of the blowing agent to form the article. Thereaction of the blowing agent and the isocyanate typically forms urealinkages and carbon dioxide to crosslink and foam the article. The gasmay also be generated if the blowing agent boils. Through the process ofnucleation, the gas foams the reaction mixture thereby forming voids orcells in the polyurethane foam article; the article of the presentinvention having about 50% open cells and 50% closed cells. Aparticularly suitable blowing agent is water. Alternatively, chemicalblowing agents may be used with a physical blowing agents such ashydrocarbons, CFC's and HCFC's, N₂ and CO₂ and combinations thereof. Theamount of the blowing agent used typically depends on a desired densityof the article. Typically, the amount of the blowing agent used is offrom about 0.8 to about 10 parts by weight based on 100 parts by weightthe composition.

EXAMPLES

Examples 1-4 and Comparative Example 1 are described herein. A series ofexamples of rigid polyurethane foam articles (Examples 1-4) are formedusing resin compositions described below in Table 1. The chemical andphysical performance properties of Examples 1-4 and Comparative Example1, such as overall foam structure and adhesion to thermoplasticsubstrates, are able to be tested.

The amounts in Table 1 are in parts by weight based on 100 parts byweight of the compositions. The compositions set forth in Table 1 arereacted at an isocyanate index of 110 to form the rigid polyurethanefoam articles. As well known in the art, isocyanate index is a measureof an actual molar amount of isocyanate reacted with the compositionrelative to a theoretical molar amount of isocyanate needed to reactwith an equivalent molar amount of the composition and isocyanate indexis calculated using the following formula:

${{Isocyanate}\mspace{14mu}{Index}} = {\frac{{Actual}\mspace{14mu}{amount}\mspace{14mu}{of}\mspace{14mu}{isocyanate}\mspace{14mu}{used}}{{Theoretical}\mspace{14mu}{amount}\mspace{14mu}{of}\mspace{14mu}{isocyanate}\mspace{14mu}{required}} \times 100}$

TABLE 1 Resin Exam- Comparative Composition ple 1 Example 2 Example 3Example 4 Example 1 Polyol A 29.20 29.90 29.20 25.80 — Polyol B 45.0046.30 45.00 50.67 45.00 Polyol C 10.00 10.30 10.00 — — Polyol D — — —10.14 — Polyol E — — — — 29.20 Polyol F — — — — 10.00 Blowing 6.50 6.706.50 5.53 6.50 Agent Aprotic 5.00 2.50 5.00 4.61 — Solvent A Aprotic — —— — 5.00 Solvent B Surfactant A 1.50 — — — — Cell Opening 1.00 — — — —Agent A Surfactant B — 1.50 1.50 1.38 1.50 Cell Opening — 1.00 1.00 1.011.00 Agent B Catalyst A 1.00 1.00 1.00 — 1.00 Catalyst B 0.50 0.50 0.50— 0.50 Catalyst C 0.30 0.30 0.30 0.40 0.30 Catalyst D — — — 0.46 — TotalResin 100.00 100.00 100.00 100.00 100.00 Composition Isocyanate 110 110110 110 110 Index Polyol A is PEL-SOY ™ 744, a biopolyol formed from soyoil and sold under the trademark PEL-SOY ™ 744. Polyol B is PLURACOL ®SG-360, a biopolyol formed from sacharose and sold under the trademarkPLURACOL ®. Polyol C is PLURACOL ® P-735, a supplemental polyol that isformed from trimethylolpropane and sold under the trademark PLURACOL ®.Polyol D is PLURACOL ® P-2097, a supplemental polyol sold under thetrademark PLURACOL ®. Polyol E is PLURACOL ® GP-730, a supplementalpolyol that is formed from glycerin and sold under the trademarkPLURACOL ®. Polyol F is PLURACOL ® P-1158, a supplemental polyol formedfrom trimethylolpropane and sold under the trademark PLURACOL ®. TheBlowing Agent is water. Aprotic Solvent A is triethyl phosphate. AproticSolvent B is propylene carbonate. Cell Opening Agent A is oleic acid.Cell Opening Agent B is ORTEGOL ™ 501, a cell opening agent sold underthe trademark ORTEGOL ™. Surfactant A is DABCO ® DC 5604, a surfactantformed from silicone and sold under the trademark DABCO ®. Surfactant Bis TEGOSTAB ™ B 8433, a surfactant formed from silicone and sold underthe trademark TEGOSTAB ™. Catalyst A is DABCO ® DMCHA, an amine catalystsold under the trademark DABCO ®. Catalyst B is DABCO ® 33LV, an aminecatalyst sold under the trademark DABCO ®. Catalyst C is DABCO ® BL17,an amine catalyst sold under the trademark DABCO ®. Catalyst D isPOLYCAT ® 12, a bis(dimethylaminoethyl)ether catalyst sold under thetrademark POLYCAT ®. Isocyanate is LUPRANATE ® M20S, an isocyanate soldunder the tradename LUPRANATE ®.

The rigid polyurethane foam articles of Examples 1-4 and ComparativeExample 1 are prepared and mixed with a stoichiometric excess of theisocyanate at room temperature to form reaction mixtures. The reactionmixtures are processed with a Linden machine having an impingement mixhead. More specifically, the reaction mixtures are processed at 1720 RPMfor 5 seconds with an injection pressure of 2000 PSI. Once processed,250 grams of a reaction mixture is injected into a mold and thereafterexpands to fill the mold and form the rigid polyurethane foam article.After formation, the rigid polyurethane foam article is evaluated todetermine adhesive strength, cell strength, flow, porosity andshrinkage.

Adhesive strength is measured according to ASTM D413. Adhesive strengthis a measure of a force required to remove a thermoplastic coupon froman exterior of a rigid polyurethane foam plaque (herein referred to as afoam plaque). The foam plaque is 12×12×2 inches in dimension, has atarget density of 1.86 Lb/ft³, and has thermoplastic coupons secured tothe exterior surface thereof. Thermoplastic coupons are cut frompolypropylene and other substrates of commercial importance todimensions specified in ASTM D413. Prior to forming and molding, flametreated thermoplastic coupons are secured to the sidewalls of a 12×12×2inch mold. Next, 141 grams of each of the reaction mixtures describedabove, at ambient temperature, are sequentially injected into moldshaving temperatures of 115-120° F. to form the foam plaques. Afterforming, the foam plaques are removed from the mold and have thethermoplastic coupons secured to the exterior surfaces thereof. AnInstron is used to measure the force required to separate thethermoplastic coupons from the foam plaques at 0.05 inches per minute.Generally, maximized adhesive strength values (PSI) are desired. Theadhesive strength of Example 2 is greater than the adhesive strength ofExample 3, i.e., the adhesive strength improves as the amount of AproticSolvent A in the resin composition is increased. In addition, theadhesive strength of Example 3 is greater than the adhesive strength ofComparative Example 1, which is formed from a resin composition withoutAprotic Solvent A.

Cell strength is an observation of the puncture resistance of the rigidpolyurethane foam article. The test entails the forceful application ofa probe on the rigid polyurethane foam article by one skilled in theart.

Back pressure is evaluated by pouring 250 grams of each of the reactionmixtures into cups and allowing the rigid polyurethane foam articles toform in the cups. When the rigid polyurethane foam articles form in thecups, voids are typically formed at the bottoms of the cups andsubjectively examined to determine whether there is adequate backpressure based on the characteristics of the molded sample. Generally,if the cup fills up completely, flow is adequate.

Porosity is measured according to ASTM D6226. Porosity is a numericaldetermination of an amount of open cells in the rigid polyurethane foamarticle, i.e., an accessible cellular volume of the rigid polyurethanefoam article as a percentage. Generally, lower porosity valuescontribute to improved performance properties and allow for moreefficient processing of the rigid polyurethane foam article.

Shrinkage is determined by a visual observation of the molding processas well as an objective observation as to changes in dimension of therigid polyurethane foam article over time. Dimensional stability of therigid polyurethane foam article is desired.

Example 1 exhibits excellent adhesive strength, cell strength, flow, andshrinkage. These properties result, at least in part, from the selectionof polyols A and B, i.e., the polyols of this invention. Still further,the excellent adhesion strength results, in part, from Aprotic SolventA. The adhesive strength of Example 3 demonstrates an impact of AproticSolvent A. Still further, the excellent porosity results, in part, fromCell Opening Agent A. Together, a relationship is demonstrated betweenperformance properties, such as adhesive strength, cell strength, andporosity, and changes to the resin composition of the subject invention.

Comparative Example 1 is conventional rigid polyurethane foam article.Comparative Example 1 exhibits adequate adhesion to thermoplasticsubstrates, cell strength, flow, porosity and shrinkage. However,Comparative Example 1 does not have the significant levels of biobasedchemicals and the chemical stability of the subject invention.

Accordingly, the examples demonstrate the use of the resin compositionthat is (a) chemically stable in the presence of water and (b) includesbiopolyols and other environmentally friendly components to form a rigidpolyurethane foam article having excellent adhesion to thermoplasticsubstrates, cell strength, flow, porosity, shrinkage and overall foamstructure.

The present invention has been described in an illustrative manner, andit is to be understood that the terminology which has been used isintended to be in the nature of words of description rather than oflimitation. Obviously, many modifications and variations of the presentinvention are possible in light of the above teachings. It is,therefore, to be understood that within the scope of the appendedclaims, the present invention may be practiced otherwise than asspecifically described.

What is claimed is:
 1. A rigid polyurethane foam article comprising thereaction product of: (A) a bioresin composition substantially free ofaprotic solvents that chemically decompose in the presence of water,said bioresin composition comprising: (i) a first biopolyol comprising anatural oil component, said first biopolyol having: (a) a nominalfunctionality of at least 2.5, (b) a hydroxyl number of from about 375to about 575 mg KOH/g, and (c) a viscosity of from about 500 cps toabout 1500 cps at 77° F., (ii) a second biopolyol comprising thereaction product of a natural carbohydrate and an alkylene oxide,wherein said second biopolyol and said first biopolyol are present in aweight ratio of greater than 1:1 to about 3:1, and (iii) an aproticsolvent that does not chemically decompose in the presence of water; and(B) an isocyanate; in the presence of (C) a chemical blowing agent.
 2. Arigid polyurethane foam article as set forth in claim 1 wherein saidsecond biopolyol and said first biopolyol are present in a weight ratioof greater than 1:1 to about 2.5:1.
 3. A rigid polyurethane foam articleas set forth in claim 1 wherein said natural oil component comprises anatural oil, the reaction product of a natural oil and a compoundreactive therewith, and a combination thereof.
 4. A rigid polyurethanefoam article as set forth in claim 3 wherein said natural oil isselected from the group of canola oil, castor oil, peanut oil, corn oil,soy oil, other vegetable oils, and combinations thereof.
 5. A rigidpolyurethane foam article as set forth in claim 3 wherein said naturaloil is soy oil.
 6. A rigid polyurethane foam article as set forth inclaim 1 wherein said natural carbohydrate is selected from the group ofa sugar, sugar alcohol and combinations thereof.
 7. A rigid polyurethanefoam article as set forth in claim 6 wherein said sugar comprises adisaccharide and said sugar alcohol comprises a triglyceride.
 8. A rigidpolyurethane foam article as set forth in claim 7 wherein saiddisaccharide is saccharose.
 9. A rigid polyurethane foam article as setforth in claim 7 wherein said triglyceride is glycerin.
 10. A rigidpolyurethane foam article as set forth in claim 8 wherein said secondbiopolyol has a nominal functionality of at least 4, a hydroxyl numberof from about 360 to about 375 mg KOH/g, and a viscosity of from about3000 cps to about 4000 cps at 77° F.
 11. A rigid polyurethane foamarticle as set forth in claim 1 further comprising a supplemental polyolthat is different than said first and second biopolyols and is not abiopolyol.
 12. A rigid polyurethane foam article as set forth in claim11 wherein said supplemental polyol is present in an amount no greaterthan about 20 parts by weight based on 100 parts by weight of saidbioresin composition.
 13. A rigid polyurethane foam article as set forthin claim 1 wherein said aprotic solvent that does not chemicallydecompose in the presence of water is selected from the group ofdimethyl sulfoxide, dimethylformamide, dioxane,hexamethylphosphorotriamide, tetrahydrofuran, triethyl phosphate, andcombinations thereof.
 14. A rigid polyurethane foam article as set forthin claim 1 wherein said aprotic solvent that does not chemicallydecompose in the presence of water is triethyl phosphate.
 15. A rigidpolyurethane foam article as set forth in claim 1 further comprising afatty acid as a cell opening agent.
 16. A rigid polyurethane foamarticle as set forth in claim 15 wherein said fatty acid is oleic acid.17. A rigid polyurethane foam article as set forth in claim 15 whereinsaid cell opening agent is present in an amount of from about 0.1 toabout 11 parts by weight based on 100 parts by weight of said bioresincomposition.
 18. A rigid polyurethane foam article as set forth in claim13 wherein said isocyanate comprises an isocyanate selected from thegroup of polymeric diphenylmethane diisocyanates (pMDIs),diphenylmethane diisocyanates (MDIs), toluene diisocyanates (TDIs),hexamethylene diisocyanates (HDIs), isophorone diisocyanates (IPDIs),and combinations thereof.